関連ワード:  do a negative plus a negative equal a positive    does a negative plus a negative equal a positive number    can a negative plus a negative equal a positive    do a negative times a negative equal a positive    does a negative subtract a negative equal a positive    does a negative plus a negative always equal a positive    will a negative times a negative equal a positive    can a negative times a negative equal a positive    in math does a negative plus a negative equal a positive    does a negative times a negative always equal a positive  
結果 : do a negative plus a negative equal a positive